Coated fabric and the production thereof



Patented July 23, 1940 UNITED STATES COATED FABRIC AND THE PRODUCTIONTHEREOF John Heron McGill, Denton, Manchester, England, assignor toImperial Chemical Industries Limited, a corporation of Great Britain NoDrawing. Application January 6, 1939, Se-

rial No. 249,591. In Great Britain January 19, 1938 18 Claims.

The present invention relates to improvements in the art of producingcoated fabrics, for example leather-cloth, tarpaulin and the like, ofthe kind comprising-a fibrous base ma'terial, such as cotton, hessian,pulp or paper, covered with a composition containing dissolvednitrocellulose and a softening agent therefor. The inven-' Anti-oxidantmaterials are often introduced to avoid this defect, but the presence ofan antioxidant often induces certain other disadvantages. Moreover, whencoatedfabrics containing substantial proportions of these softeners areheated to a temperature of about 70 0. they exude droplets of oil on thesurface of the fabric.

Softeners such as tricresyl phosphate have been proposed for use insteadof the above-mentioned vegetable oils. Softeners of this type are goodsolvents for nitrocellulose. and compare favourably with vegetable-oilsofteners in that they do not become rancid on storage. nor exude whenthe coated fabrics are heated. However, they still suffer from thedisadvantages that nitrocellulose compositions containing them insubstantial proportions are thermoplastic even after removal of anyvolatile solvents and/or diluents, and that in consequence fabricscoated with such compositions may become tacky or sticky when warm. Thisdefect is particularly troublesome if it appears during manufacturingprocesses, such as the production of coated material in continuous websby hot-plate spreading machines which involves lapping the hot coatedmaterial in folds, and in the embossing of the coated material.

A method of manufacturing coated fabrics has also been suggestedaccording to which the coating composition contains nitrocellulose and,as a softening agent therefor, a brominated tricresyl phosphatecorresponding substantially in composition to a dibromotricresylphosphate in which both the bromine atoms are substituted in thenucleus. The fabrics so coated are satisfactorily flexible at ordinarytemperatures and do not become tacky or sticky while warm, anddifficulties due to the thermoplasticity of the coating are notencountered in the usual manualthough the dibromotricresyl phosphatepossesses only a faint odour, this odour is persistent and isintensified by warmth. In certain circumstances, e. g. the exposure of alarge surface of coated fabric in an enclosed space, the odour maybecome objectionable.

This invention has as an object to devise a method of manufacturingcoated fabrics comprising a fibrous base covered with a compositioncontaining dissolved nitrocellulose and a softening agent therefor whichwill be fire-resistant, odourless, and will neither be tacky nor exudedrops of oil when warm. A further object is to provide new coatedfabrics having these properties. A still further object is to devise anew method of manufacturing coated fabrics. A still further object is toprovide new coated fabrics. Further objects will appear hereinafter.These objects are accomplished by the following invention.

I have now found that coated fabrics having a particularly highexudation temperature, satisfactory freedom formthermoplasticity, goodfire-resistance and other desirable properties, are obtained by the usein the coating composition, as softening agent for the nitrocellulose,

of a condensation product of reaction between castor oil and apolycarboxylic acid or an anhydride thereof, if desired in presence of apolyhydric alcohol; said condensation product containing a halogensubstituent.

According to the present invention, a coated fabric is produced by aprocess comprising the application to a base material of a coatingcomposition comprising colloided nitrocellulose and, as a softeningagent for the nitrocellulose. a condensation product of reaction betweencastor oil and a polycarboxylic acid, if desired in presence of apolyhydric alcohol; the said condensation product containing a halogensubstituent.

Any nitrocellulose of the type usually employed for the manufacture ofcoated fabrics in which castor oil is used as softening agent may beemployed. when the viscous or resinous halogenatedcastor-oil-pclybasic-acid condensation product is employed as solesoftening agent, the exudation temperature of the coated fabric may beas high as about 120 C.; but other softening. agents, either of thesolvent type for instance tricresyl phosphate, or of the type havinglittle or no solvent action, such as castor oil, may be employed inpartial replacement thereof to a limited extent. For example a coatedfabric still having an exudation temperature as high as about 100 C. mayb tained by employing, as softener for the nitrocellulose, a brominatedcastor oil citrate containing 15% or less bromine in conjunction withhalf its weight of castor oil; whereas when castor In the manufacture ofan artificial leather, a fireproofed cotton fabric is coated in a knownmanner with a composition consisting of the following ingredients inparts by weight.

Parts Nitrocellulose (11.4%1l.8% nitrogen) 16 White pigment (titaniumoxide) l1 Resin consisting of brominated castor oil citrate with 5%bromine 33 Solvent mixture (ethyl acetate: industrial spirits 40:60 byvolume) The product may be embossed.

Example 2 Parts Nitrocellulose (l0.8%11.0% nitrogen) 30 Pigment 30Magnesium ammonium phosphate 15 Resin consisting of brominated castoroil citrate containing 15% bromine 60 'h'icresyl phosphate 16 Solventmixture as in Example 1 120 The composition is spread on a flreproofedcotton fabric.

Example 3 Anreproofed cotton base fabric is coated in the usual way withthe following composition:

Parts Nitrocellulose (l0.8-11.0% nitrogen) 30 Pigment 30 Magnesiumammonium phosphate l5 Resin consisting of a castor-oil-modified glycerolphthalic acid condensation product containing 18% bromine 60. 'Iricresylphosphate 16 Solvent mixture as in Example 1 120 The .coated cloth maybe stamped or embossed.

Example I A fireproofed cotton base fabric is coated with the followingcomposition:

Parts Nitrocellulose (as in Example 2) 30 Pigment 30 Magnesium ammoniumphosphate 15 Castor-oil-maleic-acid condensation products containing 13%bromine 60 Tricresyl phosphate 18 Solvent mixture as in Example 1 120The coated cloth may be stamped or embossed.

Example 5 A fireproofed cotton base fabric is coated with the followingcomposition:

Parts Nitrocellulose (as in Example 2) 16 White pigment (titanium oxide)11 Castor-oil-citric-acid condensation product containing 5% chlorine 83Solvent mixture as in Example 1 80 The coated cloth may be stamped orembossed.

Instead of the condensation products used in the examples I could haveused any halogenated 5792/38 flied February 23, 1938.

. rial No. 217,775, filed July 6, 1938, in the name of Arthur Hill, bytreating a viscous or plastic poly-- basic carboxylic ester of castoroil-in solution in a suitable solvent with bromine until between 5%25%,and preferably between 10%-20% of bromine is introduced, reckoned on theweight of the untreated castor-oil-polybasic-carboxylicacid reactionproduct. There may thus be employed for example the condensed castor oilcitrates brominated to the extent of 15% of the final product.

Alteinatively, the condensation product used may be one obtained by thehalogenation of a castor-oil-modiiled polyhyciric-alcohol-polybasicacidcondensation product; for instance one produced as described in Britishapplication No.

The chlorinated condensation products of castor oil and polybasicorganic acids, whether or not also condensed with Dolyhydric alcohols,e. g. the chlorinated castor oil citratescontaining 542.5% chlorine, arealso suitable for use according to my invention. In the application ofmy invention, I may make use of the halogenated condensation products ofcastor oil and any one of the followin polycarboxylic acids: maleic,fumaric. citric, aconitic. tartaric, phthalic. isophthalic.terephthalic, hexahydrophthalic. succinic, adipic, glutaric, azelaic,suberic and sebacic acids. These intermediate condensation products mayif desired also contain a proportion of glycerol or ethylene glycolcondensed therein. The halogenation should be carried out to the extentof between .06 and .3 gm. molecules of halogen for each grms. of theunheated condensation product and preferably between .125 grm. mole and.25 grm. mols.

The softeners used according to the present invention, besidespossessing improved flameresistance, are characterised by low volatilityand an almost complete lack of odour. Coated fabrics made according tothe present invention are practically odouriess and do not propagatetheir own combustion. In general. an increase in the bromine content ofthese softeners corresponds to a higher flame-resistance. Softeners ofthis type containing over 15% bromine may be strongly coloured, and mayaccordingly be used preferably in dark-coloured coating compositions.

Highly brominated softenersare preferably used in presence of aproportion of solvent softener. e. g. tricreeyl phosphate.

As many apparently widely different embodiments of this invention may bemade without departing from the spirit and scope thereof, it is to beunderstood that the invention is not limited to the specific embodimentsthereof except as defined in the appended claims.

I claim: I

1. A process for the production of coated fabrics which comprises theapplication to a base material of a flame resistant coating compositioncomprising colloided nitrocellulose and. as a softening agent therefor,a substance of the class consisting of the condensation products of areaction between castor oil, a halogen and a polycarboxylic acid, andthe condensation products of a reaction between castor oil. a halogenand a polycarboxylic acid in the presence of a polyhydric alcohol. thehalogen content of the condensation product being between .06 and .3gram molecules of halogen for every 100 grams of the unheatedcondensation 'roduct.

2. A process as in c 1. in which the softenins agent also contains aminor proportion of a solvent softener for the nitrocellulose.

- 3. A process as in claim 1, in which the halogenated condensationproduct is a brominated castor-oll-citric-acid condensation product.

4. A process as claimed in claim 1 in which the halogenated condensationproduct contains from .125 to .25 grm. molecules of halogen for everyhundred grammes of the unheated condensation product.

5. A process as in claim 1, in which the halogenated condensationproduct contains 5%-25% of bromine on the weight of the unheatedcondensation product.

6. A process as in claim 1, in which the halogenated condensationproduct contains 10-20% of bromine on the weight of the unheatedcondensation product.

7. A process as claimed in claim 1 in which the halogenated condensationproduct contains from 5% to 12.5% of chlorine'calculated on the weightof the unheated condensation product.

8. A process as claimed in claim 1 in which the halogenated-condensationproduct contains from 5% to 10% of chlorine calculated on the weight ofthe unheated condensation product.

9. Flame resistant coating compositions comprising colloidednitrocelluloseand, as a softening agent therefor, a substance oftheclass consisting of the condensation products of a reactionbetween-caster oil, a halogen and a polycarboxylic acid, and thecondensation products of a reaction between castor oil, a. halogen and apolycarbox'ylic acid in the presence of a polyhydric alcohol, thehalogen content of the condensation product being between .06 and .3gram molecules of halogen for every 100 grams of the unheatedcondensation product. p

10. Coating compositions as claimed in claim 9,

cnnrxncsra or coanscr ron.

Patent No. 2,208,6h0,'

in which the softening agent also contains a minor proportion of asolvent softener for the nitrocellulose.

11. Coating compositions as claimed in claim 9, in which the halogenatedcondensation product is a brominated castor-oil-citric acid condensa-.tion product.

12. Coating compositions as claimed in claim 9 in which the halogenatedcondensation product contains from .125 to .25 grm. molecules of halogenfor every hundred grammes of unheated con densation product. I

13. Coating compositions as claimed in claim 9, in which the halogenatedcondensation product contains 5%-25% of bromine on the weight of theunheated condensation product.

14. Coating compositions as claimed in claim 9, in which the halogenatedcondensation product contains from 5 to 12.5% of chlorine calculated onthe weight of the unheated condensation product.

15. Coating compositions as claimed in claim 9, on the weight of theunheated condensation contains from 10 to 20% of bromine calculated onthe weight of the unheated condensation product.

16. Coating compositions as claimed in claim 9. in which the halogenatedcondensation product contains from 5 to 10% of chlorine calculated onthe weight of the unheated condensation product.

17. Coated fabrics comprising a textile material and a composition asclaimed in claim 9.

18. Coated fabrics comprising a textile material and a composition asclaimed in claim 9 in which the softening agent also contains a minorproportion of a solvent softener for the nitrocellulose.

- JOHN HERON McGILL.

July 191 .0;

JOHN HERON heGILL.

It is hereby certified that error appears in the printed specificationof the'above numbered patent requiring correction as follower Page 1',sec-- 0nd column, line 25, for the word "form" read --from--; page 5,second column, line 25, claim 15, for "on the weight of the unheatedcondensation" read --in which the halogenated condensationproduotandthat the said Letters Patent should be read withth iscorrectiontherein that the same may conform to the record of the case inthe Patent Office.

sighed and sealed ems 10m day of September, a. p. 191 0.

(Seal) Acting Commissioner ofPatents.

CERTIFICATE OF CORRECT ION. Patent No. 2,2o ,6uo July 25, ll o JOHNHERON McGILL.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows: Page 1,second column, line 25, for the word "form" read --from--; page 5,second column, line 25, claim 15, for "on the weight of the unheatedcondensation" read --in which the halogenated condensation productandthat the said Letters Patent should be read with this correction thereinthat the same may cenform to the record of the case in the PatentOffice. Signed and sealed this 10th day of September, A. D. 191m.

(Seal) Acting Comniis eioner ofPatents.

